Influence of thermal treatment on formation of volatile compounds,cooking loss and lipid oxidation in foal meat

The influence of four different cooking methods (roasting, grilling, microwaving baking and frying with olive oil) on volatile compounds profile (using solid phase microextraction coupled to GC–MS), lipid oxidation (by TBARs measurement) and cooking loss of foal meat was studied. Cooking losses were significantly (P < 0.001) affected by thermal treatment, being higher (29.9%) after microwaving and lower after grilling (19.1%) treatments. As expected, all the cooking methods increased TBARs content, since high temperature during cooking seems to cause an increase of the oxidation processes in foal steaks, being this increment significantly (P < 0.001) higher when foal steaks were roasted or microwaved.     

Effects of four cooking methods on the heavy metal concentrations of sea bass fillets (Dicentrarchus labrax Linne, 1785)

Heavy metals (Pb, Cd, Cr, Co, As, Ni) were analysed in cooked sea bass (Dicentrachus labrax). Different cooking treatments were used (baking, grilling, microwaving and frying). The results obtained were statistically compared with those of raw fish. The Co concentrations were below limits of detection in all samples (<0.05). Furthermore, Cr in fried samples and Ni in raw fish were not detected. Cd was only detected in microwaved samples. The Pb concentrations of microwaved and baked fish were significantly decreased. The As concentrations of fried and microwaved samples were significantly increased. The Cd and As concentrations of the fillets subjected to microwave cooking were 0.741 and 1.41 mg/kg, respectively. However, the As concentration was also significantly increased in fried samples. This value was 2.66 mg/kg. Microwaving and frying are not suitable for sea bass.     

Effects of different cooking methods on the mineral contents of wild and farmed sea bream (Sparus aurata)

The effects of different cooking methods (steaming, boiling, oven cooking, grilling, frying in olive oil, frying in soybean oil, frying in corn oil and frying in sunflower oil) on mineral contents (Ca, Mg, K, Na, Fe, Zn, Cu and Mn) of wild and farmed sea bream (Sparus aurata) were determined. The moisture rate decreased significantly (P < 0.05) after boiling, grilling, oven cooking and frying but remains stable after steaming. The fat content increased with different frying treatments. The Ca, Mg, Na, K and Zn contents of wild and farmed sea bream cooked by almost all methods significantly decreased (P < 0.05). The Cu content in grilled wild and farmed sea bream increased significantly (P < 0.05). Losses of mineral content in fried sea bream were higher than those of fish cooked by other methods. On comparing the raw and cooked fish, the results indicated that cooking had considerable effect on the mineral contents.     

Mechanisms of Docosahexaenoic and Eicosapentaenoic Acid Loss from Pacific Saury and Comparison of Their Retention Rates after Various Cooking Methods

The docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) contents of Pacific saury (Cololabis saira), a fatty fish and staple of the Japanese diet, have been reported to decrease after cooking. This study compared the DHA and EPA contents remaining in saury after grilling, pan‐frying or deep‐frying to center temperatures of 75, 85, or 95 °C, and examined physical loss, lipid oxidation, and thermal degradation as mechanisms of DHA and EPA loss. Temperature changes inside the saury were monitored using thermocouples, while DHA and EPA contents, oxygen radical absorbance capacity, and measurements of lipid oxidation (that is, carbonyl value and thiobarbituric acid value) were determined chemically. Visualization of temperature distribution inside fish samples during cooking revealed large differences in heat transfer among cooking methods. True retention rates in grilled (DHA: 84 ± 15%; EPA: 87 ± 14%) and pan‐fried samples (DHA: 85 ± 16%; EPA: 77 ± 17%) were significantly higher than deep‐fried samples (DHA: 58 ± 17%; EPA: 51 ± 18%), but were not affected by final center temperatures despite differences in cooking times. Physical loss via cooking losses (grilling and pan‐frying) or migration into frying oil (deep‐frying) accounted for large quantities of DHA and EPA loss, while lipid oxidation and thermal degradation did not appear to be major mechanisms of loss. The antioxidant capacity of saury was not significantly affected by cooking treatments. The results of this study suggest that minimization of physical losses during cooking may increase DHA and EPA contents retained in cooked Pacific saury.     

Effect of varying the gas headspace to meat ratio on the quality and shelf-life of beef steaks packaged in high oxygen modified atmosphere packs

Beef steaks (M. longissimus dorsi) were stored in modified atmosphere packs (MAP) (80% O₂:20% CO₂) with gas headspace to meat ratios of 2:1, 1:1 and 0.5:1 for 14 days at 4 °C. The pH, surface colour, texture and microbiology of beef steaks were unaffected (P > 0.05) by varying the gas headspace to meat ratio. APLSR (ANOVA-partial least squares regression) and jack-knife uncertainty testing indicated that lipid oxidation (TBARS) was significantly positively correlated with days 10 (P < 0.05) and 14 (P < 0.001) of storage. Chemical and sensory detection of lipid oxidation in beef steaks were in agreement on day 14 of storage. The sensory quality and acceptability of beef steaks were similar in gas headspace to meat ratios of 2:1 or 1:1 and unacceptable in 0.5:1. Results indicate that pack size and gas volume can be reduced without negatively affecting fresh beef quality and shelf-life.     

In-home consumer and shear force evaluation of steaks from the M. serratus ventralis thoracis

The M. serratus ventralis thoracis was obtained from US Select arm chucks (n = 87) to investigate if this underutilized muscle can be used as a steak alternative. Muscles were assigned randomly into three treatment groups: (1) control; (2) blade tenderization; and (3) injection, containing salt, phosphate, and papain. Steaks were cut from each muscle for in-home consumer evaluation (n = 136) and Warner–Bratzler shear (WBS) force determination. The WBS values for injected steaks (13.1 N) were lower (P < 0.05) than for blade-tenderized (18.4 N) and control (19.9 N) steaks. Tenderness ratings for the injected steaks were higher (P < 0.05) compared to the other treatments when steaks were grilled, oven prepared or were cooked in a skillet; however, this improvement did not significantly influence overall like scores for steaks that were oven prepared or cooked in a skillet. For the most part, degree of doneness did not significantly impact consumer evaluations of steaks prepared by the various cooking methods. However, there was a treatment × degree of doneness interaction for grilled-cooked steaks where increased doneness for blade-tenderized and injected steaks resulted in increased palatability ratings, whereas increased doneness for control steaks generally resulted in lowered palatability ratings. Consumer ratings and WBS values for the M. serratus ventralis thoracis indicate that merchandising steaks from this muscle may be a viable option in the marketplace, especially if blade tenderization or injection processes are used for further enhancement.     

Physicochemical and fatty acid characteristics of stewed pork as affected by cooking method and time

This study was designed to investigate the effects of cooking on physicochemical and fatty acid characteristics of stewed pork. Pre‐fried or raw pork belly cubes were stewed for 60, 90, 120, 150 or 180 min. After cooking, proximate chemical composition, texture, sensory evaluation, lipid oxidation, fatty acid profiles and cholesterol content were determined. Prolonged cooking time resulted in higher percentages of dry matter, fat and fat loss in stewed cubes (P < 0.01), and pre‐frying also increased fat loss. Tenderness and elasticity values of texture profile analysis and sensory scores were the highest for the cubes stewed for 180 min or by pre‐frying combined with stewing for 150 min. Pre‐frying and extended cooking time significantly increased lipid oxidation (P < 0.01). Cooking modified fatty acid profiles which altered the derived cardiovascular indices, and reduced cholesterol content. Prolonged stewing improved eating quality and most nutritional values of pork belly.     

A comparison of needle-free and needle-injection methods and solutions for enhancement of beef longissimus lumborum muscles

In Experiment 1, beef strip loins (n = 15) were halved and assigned to needle (N) or needle-free (NF) injection enhancement with a phosphate plus salt solution (PS) to determine effects on color, water-binding, and palatability. Pump yields tended (P = 0.08) to be higher for NF injection. Needle-injected steaks were darker (P < 0.05) on day 1 only. The NF treatment had greater instrumental tenderness and intensity of off-flavors but less cooking loss and beef flavor (both P < 0.05). In Experiment 2, strip loins (n = 28) were halved and assigned to one of four treatments: (1) N, or (2) NF injection with PS; (3) N, or (4) NF injection with a calcium lactate solution (CL) to determine effects on water-binding and palatability. Needle-free injection resulted in a greater incidence (P < 0.05) of off-flavors and abnormal texture. The PS solution resulted in greater (P < 0.05) instrumental, myofibrillar, and overall tenderness; greater juiciness; greater incidence of off-flavors and abnormal texture; and less (P < 0.05) connective tissue and cooking losses than CL. The PS and NF combination had the highest pumped yields and least cooking losses (both P < 0.05). Enhancing beef strip loins with PS and NF injection has potential to improve yield, tenderness, and juiciness but harm texture and flavor.     

Effect of different cooking methods on the oxidation,proximate and fatty acid composition of silver catfish (Rhamdia quelen) fillets

The influence of seven cooking methods (boiling, conventional baking, microwave baking, grilling, deep-frying in soybean oil, canola oil, or partially hydrogenated vegetable oil) on the oxidation, proximate and fatty acid composition of silver catfish (Rhamdia quelen) fillets was evaluated. All the treatments reduced moisture and increased the protein content. The free fatty acid content of the fillets was significantly reduced by the different cooking methods, while conjugated diene levels and peroxide values decreased for all fried samples, but remained constant in the samples subjected to the other cooking methods. Boiling and baking increased thiobarbituric acid reactive substances (TBARS), while grilling and frying did not change TBARS. Boiling, baking, and grilling did not affect the silver catfish fillets fatty acid composition. Frying in canola oil increased n−3/n−6 ratio, while frying in soybean oil increased the general polyunsaturated fatty acid content, and frying in hydrogenated vegetable oil incorporated trans fatty acids in the fillets.     

A simplified method for numerical simulation of gas grilling of non-intact beef steaks to eliminate Escherichia coli O157:H7

The objective of this work was to develop a numerical simulation method to study the heat transfer process and inactivation of Escherichia coli O157:H7 during gas grilling of non-intact beef steaks (NIBS). A finite difference and optimization algorithm was developed to determine the effective heat transfer parameters during grilling. After validation, these parameters were used in a finite element method to simulate the temperature profiles at various locations of NIBS (2.54 cm in thickness). The computer simulation results showed that E. coli O157:H7 may survive the heating processes if normal grilling conditions for intact beef steaks were used. Computer simulation results also suggested that E. coli O157:H7 might be effectively inactivated if NIBS (2.54 cm) were evenly flipped (every 4 min) and cooked for 16 min during cooking. The result of this study may help the food service industry to develop more adequate grilling methods and conditions to cook NIBS.     

Antioxidative effects of encapsulated sodium tripolyphosphate and encapsulated sodium acid pyrophosphate in ground beef patties cooked immediately after antioxidant incorporation and stored

Ground beef with 1% NaCl was incorporated with 0.5% unencapsulated sodium tripolyphosphate (uSTP), 0.5% encapsulated sodium tripolyphosphate (eSTP), 0.5% unencapsulated sodium acid pyrophosphate (uSAPP), or 0.5% encapsulated sodium acid pyrophosphate (eSAPP) prior to being cooked and stored (0 or 6 d, 3 °C). The pH was higher (P < 0.05) for sodium tripolyphosphate samples (6 d: uSTP 5.98; eSTP 5.89) and lower (P < 0.05) for sodium acid pyrophosphate (6 d: uSAPP 5.31, eSAPP 5.33) samples than control sample (6 d, 5.50). Overall, samples with uSTP had the least cooking loss and lowest TBARS values. TBARS (mg/kg) for the phosphate treatments were lower (P < 0.05; ave. 1.78, 0 d; 3.49, 6 d) than for the control samples (3.07, 0 d; 22.85, 6 d). Therefore, phosphate incorporation into ground beef prior to cooking aids in the reduction of oxidation in the cooked, stored product, although a longer period of time before thermal processing may be necessary for the encapsulated phosphate to have significant benefits.     

Effect of cooking methods on fatty acids,conjugated isomers of linoleic acid and nutritional quality of beef intramuscular fat

The effect of boiling, microwaving and grilling on the composition and nutritional quality of beef intramuscular fat from cattle fed with two diets was investigated. Longissimus lumborum muscle from 15 Alentejano young bulls fed on concentrate or pasture was analyzed. Cooking losses and, consequently, total lipids, increased directly with the cooking time and internal temperature reached by meat (microwaving > boiling > grilling). The major changes in fatty acid composition, which implicated 16 out of 34 fatty acids, resulted in higher percentages in cooked beef of SFA and MUFA and lower proportions of PUFA, relative to raw meat, while conjugated linoleic acid (CLA) isomers revealed a great stability to thermal processes. Heating decreased the PUFA/SFA ratio of meat but did not change its n−6/n−3 index. Thermal procedures induced only slight oxidative changes in meat immediately after treatment but hardly affected the true retention values of its individual fatty acids (72–168%), including CLA isomers (81–128%).     

Increasing omega-3 levels through dietary co-extruded flaxseed supplementation negatively affects pork palatability

To clarify the impact of feeding co-extruded flaxseed on carcass quality and pork palatability, 96 pigs (48 barrows and 48 gilts) were fed three different levels of flaxseed (0%, 5% and 10% of dietary intake) for 76 days. Carcass quality and meat quality characteristics of pure loin muscle and ground pork (20% fat) were evaluated. Fat hardness and belly firmness decreased (P < 0.001) with increasing co-extruded flaxseed. Pigs fed co-extruded flaxseed levels had higher lean yield (P = 0.045) and total lean content (P = 0.034). Loin from barrows had higher fat content compared to gilts (P < 0.001). Co-extruded flaxseed supplementation increased (P < 0.001) omega-3 content in loin and ground pork. Pork flavour intensity and off-flavour intensity scores lowered (P < 0.001) with increasing levels of co-extruded flaxseed, being more accentuated (P = 0.023) in reheated pork chops from barrows. Diet affected all texture and flavour sensory characteristics (P < 0.05) as tissue levels of omega-3 fatty acids increased, likely as a result of increased lipid oxidation.     

Beef quality attributes as affected by increasing the intramuscular levels of vitamin E and omega-3 fatty acids

In order to investigate the effects of increasing beef n-3 fatty acid content and the protective effects of vitamin E antioxidant activity on meat quality characteristics, 80 feedlot steers were fed 4 different diets (control, high vitamin E, 10% ground flaxseed or high vitamin E-10% ground flaxseed). While dietary treatments had no effect (P > 0.05) on meat composition or tenderness values, the increase in oxidation products was lower (P = 0.046) in meat from vitamin E supplemented steers and higher (P = 0.006) in meat from flaxseed fed animals. The increase in α-tocopherol tissue levels (P < 0.001) in meat from animals fed flaxseed and increased dietary vitamin E resulted in the lowest drip loss values (P = 0.013). As expected, display time had a large effect on retail traits in both steaks and patties (P < 0.001). While retail traits of steaks were not affected by the dietary treatments (P > 0.05), feeding flaxseed decreased (P < 0.05) ground beef retail scores, which were not corrected by higher levels of dietary vitamin E. Finally, although no effect (P > 0.05) was observed among treatments for sensory attributes in steaks, the correlations of a combined n-3:α-tocopherol ratio against retail and sensory attributes (P < 0.05) suggest that increased n-3 fatty acids levels require increased dietary antioxidants, such as vitamin E to avoid negative effects on meat quality from a loss in oxidative stability.     

Proximate and fatty acid compositions and sensory acceptability of Hispanic consumers towards rib‐eye steaks from forage‐finished steers

Proximate and fatty acid compositions and sensory acceptability of rib‐eye steaks (fresh and 6 months frozen‐stored) from three forage‐finished steers [S1 (bermudagrass + ryegrass, etc.); S2 (bermudagrass + ryegrass + berseem, etc.); S3 (bermudagrass+berseem+soybean+brown midrib sorghum, etc.)] and one commercial steak (C), cooked by one‐sided and/or two‐sided grilling, were evaluated. All forage‐finished steaks had lower [omega‐6/omega‐3] ratios than C. Sensory liking was assessed by Hispanic consumers. Raw C steak had higher fat and lower protein contents than others (S1, S2 and S3). Concerning raw steaks, S3 had higher liking scores for overall appearance and fat appearance than others. Two cooking methods did not cause significant differences in sensory liking. Juiciness and overall liking of cooked C and S3 (one‐sided grilling) steaks were not significantly different. Purchase intent (after knowing health benefits of forage‐finished steaks) increased from 62.0–73.8% to 69.8–85.7%. Forage‐finished steaks showed a potentially healthier lipid profile than grain‐finished steaks and had market potential towards Hispanic population.     

基于主成分分析法的熟化马铃薯品质评价

以‘紫花白’马铃薯为原料,研究汽蒸、水煮、微波、烘烤、Air-frying（无油）、Air-frying（加油）、油炸7 种熟化方式对其基本营养成分和核苷酸类鲜味物质、质构、色泽及感官品质的影响,并对其品质指标进行主成分分析。结果表明：汽蒸和微波可最大程度地降低马铃薯基本营养成分的损失;微波显著提升了马铃薯核苷酸类鲜味物质含量且含量最高;Air-frying（无油）显著影响马铃薯质构特性;Air-frying（加油）与油炸显著加深马铃薯色泽;水煮熟化后马铃薯感官评分最高;经主成分分析后,7 种熟化方式下马铃薯品质评价综合得分由大至小依次是：Air-frying（加油）＞微波＞油炸＞水煮＞烘烤＞汽蒸＞Air-frying（无油）。由此得出结论：汽蒸可作为马铃薯深加工前期熟化处理的较优选择;Air-frying（加油）可较好地保留其品质特性,微波可满足摄食低脂类食品消费者的需求。     

烹调加工对鱼类营养价值的影响

鱼是膳食中ω-3脂肪酸及多种维生素的良好来源,但这些营养成分经过烹调处理会受到不同程度的影响。本文综述了烧烤、油炸、微波、清蒸等烹调方法对鱼类ω-3脂肪酸及维生素保存率的影响,以及食用不同烹调处理的鱼对心血管疾病发生风险的影响,以指导合理烹调鱼类,使其充分实现营养价值。     

Physico-chemical, textural and structural characteristics of sous-vide cooked pork cheeks as affected by vacuum, cooking temperature, and cooking time

This paper describes the influence of different factors on sous-vide cooked pork. Pork cheeks were cooked at different combinations of temperature (60 °C or 80 °C), time (5 or 12 h) and vacuum (vacuum or air packaged). Weight losses were lower and moisture content higher in samples cooked for a shorter time (P = 0.054) and at a lower temperature (P < 0.001). Samples cooked at 60 °C showed more lightness (L*) and redness (a*) (P < 0.001). Lipid oxidation showed an interaction between cooking time and temperature (P = 0.007), with higher TBARs values for samples cooked for 12 h at 60 °C and lower for those cooked for 12 h at 80 °C. Samples cooked at 80 °C for 12 h showed lower (P < 0.05) values for most textural parameters than all the other types of samples. Vacuum packaging showed no influence on any of the studied variables. For the treatments evaluated, cooking temperature × time combination seems to be more important than vacuum packaging in the textural and colour parameters of pork cheeks.     

基于营养与智能感官综合比较不同烹饪方式下芫根的品质差异

为筛选出芫根的适宜烹饪方式,本研究利用氨基酸自动分析仪、电子舌和食品热量检测仪（Calory Answer）比较了5种烹饪方式（水煮、气蒸、微波、高压和油炒）下芫根游离氨基酸、整体滋味和营养成分的差异,同时对芫根的抗氧化活性进行了分析。结果表明：新鲜芫根中总游离氨基酸含量为261.06 mg/100 g,以甜味氨基酸为主,气蒸、微波和油炒后芫根中总游离氨基酸的含量分别提高90.50%、59.74%和83.92%,其中苦味氨基酸比例增加;水煮能够增加酸味和鲜味氨基酸的比例,减少苦味氨基酸比例。油炒、微波和高压能显著提高芫根的能量和碳水化合物含量,气蒸和油炒能显著提高其多酚含量和抗氧化活性（P<0.05）。电子舌能有效区分不同方式烹饪的芫根,水煮和气蒸的芫根滋味较为接近,微波和高压的相似,油炒的较其他相比滋味差异较大。主成分综合评价分析表明：芫根最适宜的烹饪方式是气蒸,其次是油炒。     

Innovative Cooking Techniques for Improving the Overall Quality of a Kailan-Hybrid Broccoli

The microbial, physical, sensory and nutritional quality of boiled (vacuum and conventional), steamed, pressure cooked, sous vide, microwaved (sous vide and conventional), deep-fried (vacuum and conventional) and grilled kailan-hybrid broccoli (Bimi®) after cooking was studied. Sous vide microwaving greatly decreased microbial counts, achieving very low psychrophilic and enterobacteria counts (1.1 and 0.2 log CFU g^?1, respectively). Vacuum boiling and sous vide reduced the stem broccoli firmness by approximately 54–58 %, reaching a pleasant and moderate softening. Sous vide, grilling and steaming induced the lowest stem colour changes. Generally, all cooking treatments showed a good overall sensory quality. The total phenolic content (1,148 mg CAE kg^?1 fw) usually increased after cooking, with microwave and grilled treatments registering the highest increases up to 2-fold. Commonly, the total antioxidant capacity (296.6 mg AAE kg^?1 fw) increased after cooking by sous vide, microwaving and frying treatments registering the highest increments, by approximately 3.6-fold. Generally, the cooking process reduced the initial vitamin C content, with vacuum and conventional boiling showing the lowest and highest losses with 27 and 62 %, respectively, while vacuum deep frying preserved the initial value (1,737 mg kg^?1 fw). As a main conclusion, the studied grilling and vacuum-based cooking treatments resulted in better microbial quality, colour, stem firmness and sensory quality than the remaining ones. This maintained or even improved the total antioxidant content of the new kailan-hybrid broccoli studied.